离心模型试验中界面土压力盒标定方法研究  

Study on calibration method of interface soil pressure sensor in centrifugal model test

作　　者：蔡正银[1] 代志宇 徐光明[1] 任国锋 CAI Zhengyin;DAI Zhiyu;XU Guangming;REN Guofeng(Geotechnical Engineering Department,Nanjing Hydraulic Research Institute,Nanjing 210024,China)

机构地区：[1]南京水利科学研究院岩土工程研究所,江苏南京210024

出　　处：《水利学报》2020年第6期695-704,共10页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(51879167);南京水利科学研究院基金项目(Y319006,Y317011,Y319012)。

摘　　要：在离心模型试验中,准确量测结构面上土压力的首要条件是采用合理的方法对界面土压力盒进行标定。本文首先使用砂雨法制备砂土土样,并考虑了出砂口尺寸和落距对制样结果的影响;然后在考虑温度变化,传感器上覆砂层厚度和砂颗粒粒径变化的情况下对BW-3型界面土压力盒分别进行了标定试验;最后将标定结果应用于相对密度为0.9的砂土静止侧压力系数测量当中。结果发现:40℃和20℃的温度变化对传感器测量结果的影响不大;砂标试验时,随着传感器上覆砂层厚度的增加,传感器输出电压的非线性趋势逐渐明显,土压力盒的标定系数逐渐增大;当采用不同颗粒粒径的砂对传感器进行标定时,标定系数与颗粒粒径的变化呈正相关趋势;通过测量不同土样的静止侧压力系数发现,土样K0值随着砂颗粒粒径的增加而逐渐减小,与Jaky公式计算结果对比证实了仅考虑有效内摩擦角计算土样K0值是不准确的。In the centrifugal model test, the first condition of accurately measuring the earth pressure on the structural surface is to use a reasonable method to calibrate the interface earth pressure sensor. In this paper, firstly, sand and soil samples are prepared by sand pourer method, and the influence of the size of sand outlet and drop distance on the results of sample preparation is considered. Secondly, BW-3 interface soil pressure sensor is calibrated under the condition of considering the change of temperature, the thickness of sand layer on the sensor and the change of sand particle size. Finally, the calibration results are applied to the measurement of static side pressure coefficient of sand with relative density of 0.9. The results show that the temperature changes of 40℃ and 20℃ have little effect on the measurement results of the sensor. In the sand standard test, the nonlinear trend of the output voltage of the sensor is gradually obvious with the increase of the thickness of the sand layer on the sensor, and the calibration coefficient of the earth pressure sensor is gradually increased. When the sand with different particle size is used to calibrate the sensor, the calibration coefficient and the particle size change are positive correlation trend:through measuring the coefficient of static lateral pressure of different soil samples, the K0 value of soil sample gradually decreases with the increase of sand particle size. Compared with the calculation results of JAKY formula, it is proved that the K0 value of soil sample calculated only considering effective internal friction angle is not accurate.

关 键 词：离心模型试验 土压力盒 标定 土压力 

分 类 号：TU432[建筑科学—岩土工程]